#include<iostream>
using namespace std;
int main()
{
	int arr[7] = {1, 1, 2, 3, 2, 4, 4};
	int ans = 0;
	for (int i = 0; i < 7; i++)
	{
		ans ^= arr[i];
	}
	cout << ans << endl;
	return 0;
}
     